Quantum Mechanics Supports Free Will


Do you believe in free will?

Some physicists and neuroscientists believe in the opposite proposition: determinism. The mathematics of quantum mechanics have a say in this argument: Determinism is impossible unless you are willing to make an even greater philosophical sacrifice.

A determinist point of view says, "If I precisely know the complete workings of a system -- i.e., the position of every particle and how the laws of the universe operate -- I can tell you exactly what it will do in all future situations." For example, by measuring the sun's gravity and the motion of solar system bodies, we can calculate whether an asteroid will hit us or how to position a satellite in a complex orbit above the Earth.

Obviously, humanity has been fairly successful at this: Science and technology underpin the modern world because we largely can understand and anticipate the actions of inanimate objects.

But are you prepared to accept that your mind follows these same rules? That it is a machine which can be completely predicted, like pool balls on a felt table or comets circling a star? That you don't make choices: the choices are already made by the wiring patterns in your brain, and you just carry them out like a colossally complex adding machine? This is the philosophical endgame of classical physics (i.e., Newtonian physics) taken to its logical conclusion.

Those who accept this philosophy simply apply physics to the human brain: If we could know all the molecules and cells and what they were doing, we could predict human thought perfectly. In practice, of course, this is nearly impossible, but it is philosophically possible. And chilling.

Then along came quantum mechanics. When physicists observed that behavior at the atomic level was fundamentally indeterminate, the universal validity of classical physics, as well as philosophical determinism came into question. Physicists recoiled at the idea that their science could no longer claim to predict all things with infinite precision. But, that's what quantum mechanics teaches us. We absolutely cannot know exactly how something will turn out before it happens.

Most physicists eventually accepted this idea as an empirical fact of measurement, but assumed that a flaw in quantum mechanics created the uncertainty. Perhaps, with further insight, some "hidden variable" could allow them to predict things with perfect certainty again.

But that never happened.

John Bell, in a famous 1964 paper, forced everyone to reconsider, both scientifically and philosophically, their support for determinism. His famous theorem, Bell's inequality, is an incredibly profound statement. This relatively simple mathematical proof, when applied to experimental results, gives us a choice: We must either give up determinism or give up the existence of an objective reality explained by science and measurable by humans with instruments. (You can read the gory details about the experiments here.)

So if experiments on quantum phenomena are reliable, then Bell concludes that determinism is false. Most physicists agree.

Essentially, quantum mechanics tells us that there are things which we cannot know about the future, things which are not predetermined but happen with some factor of chance or randomness. Although many things in the world may be predicted, everything is not predetermined, and our actions do not unfold mechanically in a manner predetermined since the very moment of the Big Bang. Free will is preserved.

Thank God/gods/lucky stars!

Tom Hartsfield is a physics Ph.D. candidate at the University of Texas and a regular contributor to the RealClearScience Newton Blog. The original post appeared here.

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New fossils suggest human ancestors evolved in Europe, not Africa

Experts argue the jaws of an ancient European ape reveal a key human ancestor.

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  • The jaw bones of an 8-million-year-old ape were discovered at Nikiti, Greece, in the '90s.
  • Researchers speculate it could be a previously unknown species and one of humanity's earliest evolutionary ancestors.
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Homo sapiens have been on earth for 200,000 years — give or take a few ten-thousand-year stretches. Much of that time is shrouded in the fog of prehistory. What we do know has been pieced together by deciphering the fossil record through the principles of evolutionary theory. Yet new discoveries contain the potential to refashion that knowledge and lead scientists to new, previously unconsidered conclusions.

A set of 8-million-year-old teeth may have done just that. Researchers recently inspected the upper and lower jaw of an ancient European ape. Their conclusions suggest that humanity's forebearers may have arisen in Europe before migrating to Africa, potentially upending a scientific consensus that has stood since Darwin's day.

Rethinking humanity's origin story

The frontispiece of Thomas Huxley's Evidence as to Man's Place in Nature (1863) sketched by natural history artist Benjamin Waterhouse Hawkins. (Photo: Wikimedia Commons)

As reported in New Scientist, the 8- to 9-million-year-old hominin jaw bones were found at Nikiti, northern Greece, in the '90s. Scientists originally pegged the chompers as belonging to a member of Ouranopithecus, an genus of extinct Eurasian ape.

David Begun, an anthropologist at the University of Toronto, and his team recently reexamined the jaw bones. They argue that the original identification was incorrect. Based on the fossil's hominin-like canines and premolar roots, they identify that the ape belongs to a previously unknown proto-hominin.

The researchers hypothesize that these proto-hominins were the evolutionary ancestors of another European great ape Graecopithecus, which the same team tentatively identified as an early hominin in 2017. Graecopithecus lived in south-east Europe 7.2 million years ago. If the premise is correct, these hominins would have migrated to Africa 7 million years ago, after undergoing much of their evolutionary development in Europe.

Begun points out that south-east Europe was once occupied by the ancestors of animals like the giraffe and rhino, too. "It's widely agreed that this was the found fauna of most of what we see in Africa today," he told New Scientists. "If the antelopes and giraffes could get into Africa 7 million years ago, why not the apes?"

He recently outlined this idea at a conference of the American Association of Physical Anthropologists.

It's worth noting that Begun has made similar hypotheses before. Writing for the Journal of Human Evolution in 2002, Begun and Elmar Heizmann of the Natural history Museum of Stuttgart discussed a great ape fossil found in Germany that they argued could be the ancestor (broadly speaking) of all living great apes and humans.

"Found in Germany 20 years ago, this specimen is about 16.5 million years old, some 1.5 million years older than similar species from East Africa," Begun said in a statement then. "It suggests that the great ape and human lineage first appeared in Eurasia and not Africa."

Migrating out of Africa

In the Descent of Man, Charles Darwin proposed that hominins descended out of Africa. Considering the relatively few fossils available at the time, it is a testament to Darwin's astuteness that his hypothesis remains the leading theory.

Since Darwin's time, we have unearthed many more fossils and discovered new evidence in genetics. As such, our African-origin story has undergone many updates and revisions since 1871. Today, it has splintered into two theories: the "out of Africa" theory and the "multi-regional" theory.

The out of Africa theory suggests that the cradle of all humanity was Africa. Homo sapiens evolved exclusively and recently on that continent. At some point in prehistory, our ancestors migrated from Africa to Eurasia and replaced other subspecies of the genus Homo, such as Neanderthals. This is the dominant theory among scientists, and current evidence seems to support it best — though, say that in some circles and be prepared for a late-night debate that goes well past last call.

The multi-regional theory suggests that humans evolved in parallel across various regions. According to this model, the hominins Homo erectus left Africa to settle across Eurasia and (maybe) Australia. These disparate populations eventually evolved into modern humans thanks to a helping dollop of gene flow.

Of course, there are the broad strokes of very nuanced models, and we're leaving a lot of discussion out. There is, for example, a debate as to whether African Homo erectus fossils should be considered alongside Asian ones or should be labeled as a different subspecies, Homo ergaster.

Proponents of the out-of-Africa model aren't sure whether non-African humans descended from a single migration out of Africa or at least two major waves of migration followed by a lot of interbreeding.

Did we head east or south of Eden?

Not all anthropologists agree with Begun and his team's conclusions. As noted by New Scientist, it is possible that the Nikiti ape is not related to hominins at all. It may have evolved similar features independently, developing teeth to eat similar foods or chew in a similar manner as early hominins.

Ultimately, Nikiti ape alone doesn't offer enough evidence to upend the out of Africa model, which is supported by a more robust fossil record and DNA evidence. But additional evidence may be uncovered to lend further credence to Begun's hypothesis or lead us to yet unconsidered ideas about humanity's evolution.